docs: def show_dockerfile():
      """Generate (or display actual) image Dockerfile"""
  
      if not nav:
          sys.exit(1)
  
      ecode = 0
      try:
          result = nav.run_query(['show-dockerfile', 'all'])
          if result:
              anchore_utils.print_result(config, result)
  
      except:
          anchore_print_err("operation failed")
          ecode = 1
  
      contexts['anchore_allimages'].clear()
      sys.exit(ecode)